reached was never fast enough for it to rise into the air. Curtiss,
however, continued his experiments, chiefly in the improvement of
his float's, and in 1910, in the Bay of San Diego (California), he
succeeded in rising from the surface with a machine fitted with one
central float and a smill balancing float in front under the elevator,
in place of the usual front wheel (see Fig. 4). Finally, Voisin,
having fitted his Canard with three Fabre floa's, obtained several
fine flights on the Seine near Billancourt Bridge in June, 1910
(Fig. 5). The hydro-aero plane was born.
Many manufacturers then commenced to fit their machines with
floats, and since that lime hydro-aeroplanes have shown themselves
capable of rivaling their elders—the ordinary aeroplanes on wheels—
provided the conditions are favourable.
Chief Principles Involved.
The principles involved are of an extremely complicated and often
diametrically opposing character, involving as they do not only the
principle of the aeroplane and the hydroplane, but that of flotational
as well as flying stability, &c, a. pot-pourri, as it were, of both aero
nautical and marine principles. So far as the immediate future of
the hydro-aeroplane is concerned, it would appear that advance is
more likely to result from practical experiment than theoretical
considerations.
Both the aeroplane and hydroplane principle of support are the
same, viz., the thrusting or sweeping downwards of a layer of air or
water in order to derive the necessary support from the reaction of
the same.
In the true hydro-aeroplane, it is one of the chief aims to
investigate by actual experiment how far these two principles can be
combined in one and the same member. When we endeavour to
drive a hydroplane over the surface of the water we have a constantly
increasing head resistance in the case of the float, and at the same
time a constantly increasing lift or support on the part of the
aeroplane surfaces in the air, which also increase; with the speed,
but far more slowly than the resistance of the water—both water
resistance and air support increase with the square of the speed—
the former with such large squares as 64, 81, 100 . . . and the
latter with such smaller squares as 9, 16, 25 . . . we may thus
be unable to raise the machine from the surface of the water, even
with the engine running all out, and this in spite of the fact that an
appreciable lift takes the float (as a whole) partly out of the water,
thereby decreasing the water resistance. Even a slight reduction in
the water resistance (thereby enable the float to hydroplane) would
enable the machine to fly. Now, suppose, instead of reducing the
water resistance we increase the area of the supporting surface,
thereby enabling the machine to fly at a reduced speed, e.g.,
supposing the machine originally designed to fly at 40 m.p.h., but
the motor will only drive it through the water at 35 m.p.h., such a
machine can be got to rise from the surface of the water either by so
improving the floats, i.e., lessening the water resistance so that the
machine can travel over the water at the necessary 40 m.p.h.,
or by increasing the surface so that the soaring speed is
reduced to 35 m.p.h. Of course, there is in the latter case
the extra weight and resistance to be allowed for and some
re-designing would probably be necessary to overcome this. There
remains still a third way in which a hpdro-aeroplane, fitted with a
motor of not quite enough power, could be got to rise, and that is by
lowering the centre of propeller thrust. The comparatively speaking
high centre of thrust which is necessary in order that the tips of the
propaller blades shall clear the water, or it may be the top of the
float or floats, tends to drive the nose of the floats under the surface
of the water, increase the resistance, and prevent hydroplaning. It
may even drive the fore parts iof the floats completely under the
water and submerge the whole machine; this necessitates placing
the centre of longitudinal flotation well ahead of the centre of gravity
which at once gives rise to special difficulties of stabilisation while in
® ®
A British Prize for Hydro-aeroplanes.
MR. MORTIMER SINGER has again generously placed at the
disposal of the Royal Aero Club a prize of ^500, and this time it is
to be utilised for the encouragement of hydro-aeroplanes. The
conditions of the competition are now under consideration, and will
be published shortly.
Naval Airmen at Dover.
UNEXPECTEDLY, in view of a high wind, five aerop'anes
descended on Dover on Monday, having flown over from East-
church. About noon, Commander Samson and Lieut. Spencer
Grey started from Eastchurch on Short tractor bipUnes, and an
hour later they were followed by Mr. McClean, Capt. Risk and
Sub-Lieut. Hewlett, the two former on Short machines, and the
last-mentioned on an 80 h. p. Farman. After partaking of lunch
with Capt. Marley, of the Dover Aero Club, Commander Samson
returned to Eastchurch, the others deciding to remain overnight.
During the afternoon, Mrs. Marley was taken for a trip by Sub-
Lieut. Hewlett.
flight. In one machine (power-driven model), experimented with
by°the writer, the machine refused to leave the water owing to the
high thrust of the propeller driving the nose of the front float into
the water. The thrust given by the propeller in pounds was known.
A cord was attached to the machine at a point on the same level as
the top of the float. A spring bahnce registering to ounces was
fastened to the cord and the machine dragged through the water,
when the pull on the balance was about two-thirds the thrust given
by the propeller, the machine left the surface of the water and
soared, hydroplaning in quite the correct manner off the surface of
the water.
This experiment alone being quite sufficient to show the advantage,
so far as hydroplaning proper is concerned, of hiving as low a
centre of thrust as possible.
It will thus be seen that we have two distinct types of hydro-aero
planes, one of which, owing mainly to its large supporting surface,
i.e., light loading, is able to rise from the water chiefly by means of
its " wing lift," scarcely hydroplaning in the true sense of the word
at all; such machines are the large biplanes which leave the water at
comparatively speaking low speeds. In the other type the true
hydro-aeroplane as opposed to the aer.iplane on floats, it is
absolutely essential that the machine should hydro-aeroplane in the
true sense of the word, such a type (but little as yet in evidence)
must be compact and, abDve all, well powered and possessed of
great speed, capable of both rising from and alighting on the surface
of rough water, possessing great strength, especially forward, and
abundant flotational stability. Such a machine is likely to tax the
powers of both designers and constructors to the utmost.
Various Types of Hydro-Aeroplanes,
Although, strictly speaking, there is but one type of hydro
aeroplane in existence, viz., that suitable for lakes and rivers, i.e., for
coast defence and lake and river sport, it is convenient to divide
them, broadly speaking, into four types :—
1. With three principal floats, either one in front and two behind,
as in the Fabre and Voisin-Canard, or two in front and one behind,
as in the Caudron (early type). The floats used are almost
invariably of the Fabre type. At the Monaco Meeting the Caudron
proved itself to be the best of this type.
2. With two long floats fairly near together (the lateral flotational
base is generally about one-third the total span), usually of the
catamaran type, placed under the principal part of the machine, as
in the Astra, Borel, Farman, Nieuport, Wright, Albatross, Sanschez-
Besa, Goupy, &c. In some a small auxiliary float is provided,
usually placed under the tail. Personally, I consider such a float
essential.
3. With ons central float, which can be long or short, as in the
earlier Curtiss, R.E.P., Train, Wakefield, Deperdussin, &c. Such
machines are almost invariably provided with " balancers " or wing-
tip floats for lateral balance.
4. The fo-called " Flying-Boat " type, i.e., the type in which the
principal float is also made to serve the purpose of the mam/use/age
as well as in the Donnet-Leveque, Curtiss (latest type), Goedeker, &c.
In order to understand why hydro-aeroplanes have been con
structed of such varied types it is only necessary to remember that
just as there are various types of boats, some specially intended for
rapids or rivers, shallows, lakes, &c, and others for the sea, so in
the future there will undoubtedly be divers types of hydro-aeroplanes,
in all probability, as has already been stated, two chief types—one
specially designed for lakes and rivers and for coast work, and the
other, which one miy perhaps, term the " mariae " hydro-aeroplane,
will be specially designed for rising from and alighting on the
surface of the sea; it is this last-named type that wants and
awaits development. It is obviously far easier to design the former
than the latter.
(To be continued.)
® ®
Farnborough to Scotland by Aeroplane,
As witness of the fact that the backwardness of the Royal
Flying Corps is not due to any lack of enthusiasm among the officers
themselves may be taken the keen interest which is being evinced in
the proposal that No. 2 Squadron, which has been ordered to the
new station at Montrose, should make the trip from Farnborough by
the airway. Major Burke is to command the station, and the officers
appointed are Capts. Becke and Longcroft, and Lieuts. Herbert,
Lawrence, Martyn and Smith-Barry. For the journey North they
are to use four B.E. and three Maurice Farmau biplanes. It is
proposed to start from Farnborough this week, and the course will
be via Derby, York and Berwick.
Aerial Engineering Works.
WE are asked by Mr. R. F. Steadman, of 126, Eswyn Road,
Tooting, S.W., to request that any customers of the Aerial Engi
neering Works (late of Balham\ who have ordered models or
parts and have not had delivery of same, will communicate with
him, as above, when he will at once see that orders are carried out.
74